Information displays, such as liquid crystal displays and rear projection screens, often rely on light-diffusing optical constructions for efficient operation and enhanced readability. Such light-diffusing constructions assume critical roles in these displays by forward scattering the light from a source without a significant loss in the intensity of the forward scattered light. This scattered, yet high transmittance, resultant light gives such displays a desirable background brightness by reducing the amount of incident light which is scattered or reflected back toward the light source. Elimination or restriction of such “backscattered” light is a key factor in designing these light-diffusing constructions. Diffusers can be incorporated into optical systems by adding an additional diffuser component to the system, or, in some cases, by incorporating diffusive properties into an existing component.
Adding additional components to an optical system has the disadvantage of introducing additional absorption and creating additional interfaces that can reflect light, thereby causing loss of illumination and other forms of image degradation. Additionally, in some multilayer systems it may be difficult or impossible to add additional components.
Incorporating diffusive properties into an existing optical component may be achieved by, for example, etching or sandblasting a surface of an existing optical component or by filling or embedding the optical component, such as an adhesive layer, with diffusive particles. However, incorporating a diffusing layer into an existing component in the system complicates component design, adds manufacturing steps, and can have an adverse effect on performance and on product yield during manufacturing. In particular, the use of particles can detract from the overall brightness or transmittance of the incident light through backscatter.